It’s hard to get kids to eat and enjoy greens during the cold winter months. That’s why growing lettuce under lights indoors is such a good idea. Not only does this gardening activity inspire kids to eat fresh, healthy greens, but it allows you to teach kids about growing food under lights.
Greens, such as lettuce, are one of the easiest foods to grow indoors under lights. Unlike tomatoes, beans, or other fruiting vegetables, you don’t have to wait for flowering and fruiting to enjoy the harvest. You only need the plants to grow large enough so that you can pick the leaves.
To get started, you’ll need a light setup. Select a typical shop light fixture. Insert grow-light or full-spectrum fluorescent tubes in the fixture. These will mimic natural sunlight conditions, giving your plants the light intensity they need. Explain to your kids that plants grown just for the leaves don’t have the same light-wavelength needs as plants grown for flowers and fruit.
Have your kids experiment with different types of lettuce varieties, such as romaine, loose-head, and salad mixes. Sow seeds in trays filled with moistened potting soil. Once the seeds germinate, turn on the lights. Have your kids experiment with the number of hours the lights are turned on and the distance from the lights to the seedlings. Gauge the growth rate of the lettuce seedlings to determine the best number of hours and distance for optimal growth.
Keep the seedlings watered and lightly fertilized with a plant food high in nitrogen. Explain that nitrogen is essential for leaf growth. Now for the fun part: harvesting. Tell your kids that lettuce can be eaten as baby greens and can be harvested as soon as the true leaves emerge. Show your kids the difference between seedling leaves and true leaves. Ask them what the advantages and disadvantages are of harvesting this early. (You’ll get tender leaves, but a smaller harvest.) Have your kids let some lettuce grow to maturity. Explain that lettuce will need thinning to form heads; have the kids thin some trays and allow others to stay crowded, and then ask them to observe the quality differences.